Re: Bug in btrfs_rename (kernel BUG at fs/btrfs/inode.c:5595!)

Josef Bacik
2010-01-14T19:00:04Z

On Thu, Jan 14, 2010 at 12:03:23PM -0500, Josef Bacik wrote:
> On Wed, Jan 13, 2010 at 09:11:59PM +0100, Tomas Carnecky wrote:
> > On 1/13/10 9:13 PM, Josef Bacik wrote:
> >> On Wed, Jan 13, 2010 at 08:09:17PM +0100, Tomas Carnecky wrote:
> >>> I was running v2.6.33-rc2-187-g08d869a and everything was ok. Today I
> >>> decided to update the kernel (to v2.6.33-rc4) and a minute or two after
> >>> logging into the gnome desktop this kernel bug appeared in dmesg. I then
> >>> went back to the old kernel but the bug didn't disappear, not even after
> >>> running btrfsck on the filesystem.
> >>>
> >> Ok will you please run with this patch? It shouldn't panic your box, since it
> >> seems ret is -EEXIST. Just watch your logs for
> >>
> >> OH NO, ORPHAN ENTRY ALREADY EXISTS FOR<number>
> >>
> >> and then look up and find all occurances of
> >>
> >> Btrfs: orphan add<number>
> >>
> >> with the stack trace and send it back to me so I can verify that nothing heinous
> >> is happening. I assume we're just racing with unlink/rename so all that needs
> >> to be done is to take that BUG_ON out, but it would be nice to know for sure.
> >
>
> Ok will you try this patch? I've not built it, so sorry if it doesn't compile
> :). Look for the "OH NO" messages again. If they show up then the problem is
> still there, if they go away the problem is fixed. I tried to reproduce this
> locally but I can't seem to do it, so you are my only hope :).
>
> By the way, this replaces the last patch I sent you, so unapply the previous
> patch and apply this one instead. Thanks,
>

Ok here's the final version of the patch I'm going to post. This replaces the
other patches that I sent you, so un-apply the last one you applied and apply
this one instead. Run this for a day and let me know if you have any problems.
If no problems I'll go ahead and post it. Thanks,

Josef

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5440bab..24cbf6b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3305,24 +3305,7 @@ static int btrfs_setattr_size(struct inode *inode, struct iattr *attr)
send_sig(SIGXFSZ, current, 0);
return -EFBIG;
}
- }
-
- ret = btrfs_reserve_metadata_space(root, 1);
- if (ret)
- return ret;
-
- trans = btrfs_start_transaction(root, 1);
- btrfs_set_trans_block_group(trans, inode);
-
- ret = btrfs_orphan_add(trans, inode);
- BUG_ON(ret);
-
- nr = trans->blocks_used;
- btrfs_end_transaction(trans, root);
- btrfs_unreserve_metadata_space(root, 1);
- btrfs_btree_balance_dirty(root, nr);

- if (attr->ia_size > inode->i_size) {
ret = btrfs_cont_expand(inode, attr->ia_size);
if (ret) {
btrfs_truncate(inode);
@@ -3337,14 +3320,26 @@ static int btrfs_setattr_size(struct inode *inode, struct iattr *attr)

ret = btrfs_update_inode(trans, root, inode);
BUG_ON(ret);
- if (inode->i_nlink > 0) {
- ret = btrfs_orphan_del(trans, inode);
- BUG_ON(ret);
- }
+
nr = trans->blocks_used;
btrfs_end_transaction(trans, root);
btrfs_btree_balance_dirty(root, nr);
return 0;
+ } else if (attr->ia_size < i_size_read(inode)) {
+ ret = btrfs_reserve_metadata_space(root, 1);
+ if (ret)
+ return ret;
+
+ trans = btrfs_start_transaction(root, 1);
+ btrfs_set_trans_block_group(trans, inode);
+
+ ret = btrfs_orphan_add(trans, inode);
+ BUG_ON(ret);
+
+ nr = trans->blocks_used;
+ btrfs_end_transaction(trans, root);
+ btrfs_unreserve_metadata_space(root, 1);
+ btrfs_btree_balance_dirty(root, nr);
}

/*
@@ -3355,10 +3350,6 @@ static int btrfs_setattr_size(struct inode *inode, struct iattr *attr)
if (attr->ia_size == 0)
BTRFS_I(inode)->ordered_data_close = 1;

- /* we don't support swapfiles, so vmtruncate shouldn't fail */
- ret = vmtruncate(inode, attr->ia_size);
- BUG_ON(ret);
-
return 0;
}

@@ -3376,7 +3367,6 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
if (err)
return err;
}
- attr->ia_valid &= ~ATTR_SIZE;

if (attr->ia_valid)
err = inode_setattr(inode, attr);